16 



ETL is not a static level, but may fluctuate considerably from 

 one locale to another and from one year to another, depending on 

 a variety of environmental, biological, and economic factors. The 

 ETL's which we use in our IPM program are still highly provisional, 

 and will most certainly need to undergo substantial refinement in 

 future years, pending further research and fuller consideration of 

 the variables influencing ETL's. This is at least a beginning. 



We employ the following sampling methods and ETL's for principal 

 pests and beneficial predators. 



Tarnished plant bug . One sticky-coated 15 x 20 cm white rec- 

 tangle (New England Insect Traps, Box 938, Amherst, MA.) is hung 

 in each sample tree at about 0.7 meters above ground and about 0.5 

 meters from the outermost foliage to monitor adult plant bug popu- 

 lations. Traps are emplaced at the silver tip stage of apple bud 

 development and removed one week after petal fall. Based on our 

 previous research, the ETL for plant bug consists of an average 

 cumulative capture of 5 adults/trap for the initial pesticide treat- 

 ment, and 3 adult/trap (disregarding captures from 0-7 days 

 after the initial treatment) for a 2nd treatment. 



European apple sawfly . One s t icky- coa t ed 15 x 20 cm white 

 rectangle (New England Insect Traps) is hung in each sample tree 

 at about 2 meters above ground and about 0.5 - 1 meter from the 

 outermost foliage (on the south side of the tree) to monitor the 

 abundance of sawfly adults. Traps are emplaced at the early pink 

 stage of bud development and removed one week after petal fall. 

 Based on our previous research, we use an ETL of average cumulative 

 capture of 4 adults/trap for the initial pesticide treatment, and 

 2 adults/trap (disregarding captures from 0-7 days after the initial 

 treatment) for a 2nd treatment. 



Green fruitworms 



From 



fruit/sample tree /sample dat 

 fruitworm larvae, and evidenc 

 work of Chapman and Lienk in 

 set the ETL at an average of 



pink through 

 e are examin 

 e of fresh f 

 New York as 

 1 larva or f 



mid-June, 30 developing 

 ed for presence of green 

 eeding injury. Using the 

 a guide, we provisionally 

 resh feeding scar/tree. 



Leaf rollers 



Alto 



pher 



male 



and 



un ti 



addi 



samp 



evid 



in N 



of 1 



, Calif 

 omone c 



leaf ro 

 redband 

 1 harve 

 t ion , f 

 le tree 

 ence of 

 ew York 



larva 



. ) bai 

 ap is 

 Her a 

 ed mal 

 s t , wi 

 rom b 1 

 /samp 1 

 fresh 

 as a 

 or f re 



One Pherocon 1 CP trap (Zoecon Corp., Palo 

 ted with a synthetic redbanded leafroller sex 

 placed in the center of each block for monitoring 

 bundance (the cap attracts both obliquebanded 

 es). The traps are in position from green tip 

 th pheromone caps renewed every 6 weeks. In 

 oom until harvest, we examine 30 developing fruit/ 

 e date for presence of leafroller larvae and 



feeding injury. Using the research of Reissig 

 guide, we provisionally set the ETL at an average 

 sh feeding scar/tree. 



Plum curculio . We examine 60 developing fruit/sample tree/ 

 sample date (1 or 2 sample dates/week) from petal fall through mid- 

 June for evidence of fresh curculio egglaying scars. The ETL is 

 provisionally set at 1 fresh egglaying scar among the 300 or 600 

 fruit sampled/block. 



